Heat-generating sheet for use in three-dimensional molding, and surface heat-generating article

ABSTRACT

The present disclosure provides a heat-generating sheet for use in three-dimensional molding including: a pseudo-sheet structure in which plural electrically conductive linear bodies extending unidirectionally are arranged spaced apart from each other, each of the electrically conductive linear bodies having a diameter of from 7 μm to 75 μm; and a resin protective layer provided at a side of one surface of the pseudo-sheet structure. In this heat-generating sheet for use in three-dimensional molding, the total thickness of layers provided at the side of the pseudo-sheet structure at which the resin protective layer is provided is from 1.5 times to 80 times the diameter of the electrically conductive linear bodies. The present disclosure also provides a surface heat-generating article in which the heat-generating sheet for use in three-dimensional molding is used.

TECHNICAL FIELD

The present disclosure relates to a heat-generating sheet for use inthree-dimensional molding, and a surface heat-generating article.

BACKGROUND ART

Heat-generating sheets are used in various kinds of applications, forexample, as heat-generating sheets for melting ice and snow,heat-generating sheets for use in heaters, and the like.

For example, Patent Document 1 discloses “a heat-generating bodyincluding: a transparent substrate; an electrically conductiveheat-generating wire provided on at least one surface of the transparentsubstrate; a bus bar electrically connected to the electricallyconductive heat-generating wire; and a power supply portion connected tothe bus bar”.

Patent Document 2 discloses “a heating element in which wires aredisposed on an adhesive”.

Further, Patent Document 3 discloses, “a transparent flexible filmheater, in which a metal fine wire portion has a line width of from 0.4μm to 50 μm, and a ratio of an area of a light transmitting portion tothe total film area is from 70 to 99.9%”.

At the same time, techniques are known in which coating of a sheet foruse in three-dimensional molding is performed while carrying outthree-dimensional molding, utilizing a three-dimensional molding method,such as TOM (Three dimension Overlay Method) molding, film insertmolding, or vacuum molding (vacuum forming). These techniques are usedin order to impart functions such as decorative characteristics andscratch resistance to the surfaces of molded articles which are used inhousings for home electrical appliances, interior parts for vehicles,interior materials for building materials, and the like (see PatentDocument 4, for example).

-   Patent Document 1: Japanese Patent Application Laid-Open (JP-A) No.    2012-134163-   Patent Document 2: Japanese Patent (JP-B) No. 4776129-   Patent Document 3: JP-A 2008-077879-   Patent Document 4: JP-A 2015-182438

SUMMARY OF INVENTION Technical Problem

Three-dimensional molding is a type of molding in which, when a sheetfor use in three-dimensional molding is subjected thereto, a pressure isapplied in the direction of sheet thickness and the sheet thickness isreduced, as the sheet extends. Accordingly, when a heat-generating sheetincluding: a pseudo-sheet structure in which electrically conductivelinear bodies are arranged; and a resin protective layer; is used as asheet for use in three-dimensional molding, there are cases wherebulging of the surface of the resin protective layer (namely, thesurface of the heat-generating sheet) may occur at portions beneathwhich the electrically conductive linear bodies are present, after theheat-generating sheet has been subjected to three-dimensional molding tobe coated on the surface of a molded article. This happens as a resultof the electrically conductive linear bodies being embedded in alayer(s) (such as an adhesive layer, the resin protective layer, etc.)adjacent to the side of the resin protective layer, due to the molding.

At the same time, however, a conductivity of heat generated from theelectrically conductive linear bodies needs to be maintained at a highlevel.

Therefore, an object of the present disclosure is to provide aheat-generating sheet for use in three-dimensional molding which has anexcellent heat-generating efficiency, and in which bulging of a sheetsurface is prevented, even after the sheet has been subjected tothree-dimensional molding.

Solution to Problem

The above mentioned problems are solved by the following means.

<1>

A heat-generating sheet for use in three-dimensional molding, theheat-generating including:

a pseudo-sheet structure in which a plurality of electrically conductivelinear bodies extending unidirectionally are arranged spaced apart fromeach other, and each of the electrically conductive linear bodies has adiameter of from 7 μm to 75 μm; and

a resin protective layer provided at a side of one surface of thepseudo-sheet structure;

wherein the total thickness of layers provided at the side of thepseudo-sheet structure at which the resin protective layer is providedis from 1.5 times to 80 times the diameter of the electricallyconductive linear bodies.

<2> The heat-generating sheet for use in three-dimensional moldingaccording to <1>, including an adhesive layer provided between thepseudo-sheet structure and the resin protective layer.<3> The heat-generating sheet for use in three-dimensional moldingaccording to <2>, wherein the ratio of the thickness of the resinprotective layer to the thickness of the adhesive layer (thickness ofthe resin protective layer/thickness of the adhesive layer) is from 1/1to 100/1.<4> The heat-generating sheet for use in three-dimensional moldingaccording to any one of <1> to <3>, wherein each of the electricallyconductive linear bodies is a linear body formed in a wave pattern.<5> The heat-generating sheet for use in three-dimensional moldingaccording to any one of <1> to <4>, wherein each of the electricallyconductive linear bodies is a linear body including a metal wire, or alinear body including an electrically conductive thread.<6> The heat-generating sheet for use in three-dimensional moldingaccording to any one of <1> to <5>, wherein each of the electricallyconductive linear bodies is a linear body including a metal wire coatedwith a carbon material.<7> The heat-generating sheet for use in three-dimensional moldingaccording to any one of <1> to <6>, wherein the plurality ofelectrically conductive linear bodies in the pseudo-sheet structure arearranged such that adjacent electrically conductive linear bodies areregularly spaced apart from each other at intervals of from 0.3 mm to12.0 mm.<8> The heat-generating sheet for use in three-dimensional moldingaccording to any one of <1> to <7>, wherein at least one layer, of thelayers provided at the side of the pseudo-sheet structure at which theresin protective layer is provided, contains a colorant.<9> The heat-generating sheet for use in three-dimensional moldingaccording to any one of <1> to <8>, wherein at least one layer, of thelayers provided at the side of the pseudo-sheet structure at which theresin protective layer is provided, contains a thermally conductiveinorganic filler.<10> The heat-generating sheet for use in three-dimensional moldingaccording to any one of <1> to <9>, further including a resin layerprovided at an opposite side of the pseudo-sheet structure from the sideat which the resin protective layer is provided.<11> A surface heat-generating article, including, on a surface of amolded article:

a surface heat-generating body including:

-   -   a pseudo-sheet structure in which electrically conductive linear        bodies are arranged spaced apart from each other, and each of        the electrically conductive linear bodies has a diameter of from        7 μm to 75 μm; and    -   a resin protective layer provided at a side of one surface of        the pseudo-sheet structure;

wherein the total thickness of layers provided at the side of thepseudo-sheet structure at which the resin protective layer is providedis from 1.5 times to 80 times the diameter of the electricallyconductive linear bodies.

Advantageous Effects of Invention

According to the present disclosure, it is possible to provide aheat-generating sheet for use in three-dimensional molding which has anexcellent heat-generating efficiency, and in which the bulging of thesheet surface is prevented, even after the sheet has been subjected tothree-dimensional molding.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic plan view illustrating a heat-generating sheet foruse in three-dimensional molding according to a present embodiment.

FIG. 2 is a schematic sectional view illustrating the heat-generatingsheet for use in three-dimensional molding according to the presentembodiment.

FIG. 3 is a schematic sectional view illustrating a first modifiedexample of the heat-generating sheet for use in three-dimensionalmolding according to the present embodiment.

FIG. 4 is a schematic plan view illustrating a second modified exampleof the heat-generating sheet for use in three-dimensional moldingaccording to the present embodiment.

FIG. 5 is a schematic plan view illustrating a third modified example ofthe heat-generating sheet for use in three-dimensional molding accordingto the present embodiment.

FIG. 6 is a schematic plan view illustrating another example of thethird modified example of the heat-generating sheet for use inthree-dimensional molding according to the present embodiment.

FIG. 7 is a schematic sectional view illustrating a surfaceheat-generating article according to the present embodiment.

FIG. 8 is a schematic sectional view illustrating a modified example(fourth modified example) of the surface heat-generating articleaccording to the present embodiment.

DESCRIPTION OF EMBODIMENTS

An embodiment as one example of the present disclosure will be describedbelow in detail. In the present specification, any numerical rangeindicated using an expression “from * to” represents a range in whichnumerical values described before and after the “to” are included in therange as the minimum value and the maximum value thereof, respectively.

<Heat-Generating Sheet for Use in Three-Dimensional Molding>

The heat-generating sheet for use in three-dimensional molding accordingto the present embodiment (hereinafter, also referred to as“heat-generating sheet”) is: a heat-generating sheet for use inthree-dimensional molding including: a pseudo-sheet structure in which aplurality of electrically conductive linear bodies extendingunidirectionally are arranged spaced apart from each other, and each ofthe electrically conductive linear bodies has a diameter of from 7 μm to75 μm; and a resin protective layer provided at the side of one surfaceof the pseudo-sheet structure; wherein the total thickness of layers(hereinafter, also referred to as “surface layers of the pseudo-sheetstructure”) provided at the side of the pseudo-sheet structure at whichthe resin protective layer is provided is from 1.5 times to 80 times thediameter of the electrically conductive linear bodies. The term“surface” as used above refers, when a two-dimensional structureconstituted of a plurality of electrically conductive linear bodies isconsidered as a sheet, to a face which corresponds to a surface of thesheet.

When the diameter of each of the electrically conductive linear bodiesis from 5 μm to 75 μm, an increase in sheet resistance of thepseudo-sheet structure can be reduced.

Further, when the total thickness of the surface layers of thepseudo-sheet structure is equal to or greater than 1.5 times thediameter of the electrically conductive linear bodies, it is possible toavoid bulging of the surface of the resin protective layer at portionsbeneath which the electrically conductive linear bodies are present,even when the electrically conductive linear bodies are embedded in alayer(s) (such as the adhesive layer, the resin protective layer, etc.)adjacent to the side of the resin protective layer, after theheat-generating sheet has been subjected to three-dimensional molding tobe coated on the surface of a molded article.

At the same time, when the total thickness of the surface layers of apseudo-sheet structure 20 is equal to or less than 80 times the diameterof electrically conductive linear bodies 22, a decrease in conductiveefficiency of the heat generated from the electrically conductive linearbodies 22 is prevented.

Accordingly, the heat-generating sheet according to the presentembodiment has an excellent heat-generating efficiency, and the bulgingof the surface of the sheet is prevented, even after the sheet has beensubjected to three-dimensional molding.

Since the bulging of the sheet surface can be avoided in theheat-generating sheet according to the present embodiment, it is alsopossible to prevent dielectric breakdown of the surface layers of thepseudo-sheet structure.

A description will be given below regarding one example of theconfiguration of the heat-generating sheet for use in three-dimensionalmolding according to the present embodiment, with reference to thedrawings.

As shown in FIG. 1 and FIG. 2, a heat-generating sheet 10 for use inthree-dimensional molding according to the present embodiment(hereinafter, also simply referred to as “sheet 10”), includes, forexample: the pseudo-sheet structure 20; a resin protective layer 30provided at the side of one surface of the pseudo-sheet structure 20; anadhesive layer 32 provided between the pseudo-sheet structure 20 and theresin protective layer 30; and a release layer 34 provided at theopposite side of the pseudo-sheet structure 20 from the side at whichthe adhesive layer 32 is provided. In other words, the sheet 10 iscomposed, for example, of the release layer 34, the pseudo-sheetstructure 20, the adhesive layer 32, and the resin protective layer 30,which are layered in this order.

The sheet 10 having the above described layer configuration will besubjected to three-dimensional molding, after peeling off the releaselayer 34 therefrom, with the face of the sheet on the side having thepseudo-sheet structure 20 facing a molded article (an adherend). At thistime, the sheet 10 covers the surface of the molded article, in a statein which the sheet 10 is adhered to the surface of the molded article byan adhesive force of the adhesive layer 32 exposed from between the “theplurality of linear bodies” constituting the pseudo-sheet structure 20.The sheet 10 having the above described layer configuration is suitablyused in TOM molding or vacuum molding (vacuum forming), amongthree-dimensional molding methods.

Since the sheet 10 has the above described layer configuration in whichthe adhesive layer 32 is provided between the pseudo-sheet structure 20and the resin protective layer 30, the resin protective layer 30 of thepseudo-sheet structure 20 (namely, the electrically conductive linearbodies 22) can be fixed easily. Further, it is possible to simplify theproduction process in the production of the sheet 10, since theformation of the pseudo-sheet structure 20 can be performed whileimmediately fixing the electrically conductive linear bodies 22 on thesurface of the adhesive layer 32.

(Pseudo-Sheet Structure)

The pseudo-sheet structure 20 is composed of a pseudo-sheet structure inwhich a plurality of the electrically conductive linear bodies 22extending unidirectionally are arranged spaced apart from each other.Specifically, the pseudo-sheet structure 20 is composed of a structurein which, for example, a plurality of the electrically conductive linearbodies 22 extending straight are arranged parallel to each other atregular intervals, in the direction perpendicular to the direction ofthe length of the electrically conductive linear bodies 22 (or thedirection in which the linear bodies extend). In other words, thepseudo-sheet structure 20 is composed of a structure in which, forexample, the electrically conductive linear bodies 22 are arranged inthe form of stripes. The plurality of the electrically conductive linearbodies 22 are preferably arranged at regular intervals, but may bearranged at irregular intervals.

In a case in which the electrically conductive linear bodies 22 in thepseudo-sheet structure 20 are arranged such that adjacent electricallyconductive linear bodies 22 are regularly spaced apart from each other,an interval L between adjacent electrically conductive linear bodies 22is preferably from 0.3 mm to 12.0 mm, and more preferably from 0.5 mm to10.0 mm, and still more preferably from 0.8 mm to 7.0 mm.

When the interval L between adjacent electrically conductive linearbodies 22 is adjusted within the range of from 0.3 mm to 12.0 mm, in acase in which the sheet 10 includes the adhesive layer 32, it ispossible to secure an exposed surface area of the adhesive layer 32exposed from between the electrically conductive linear bodies 22, andto prevent the adhesion provided by the adhesive layer 32 exposed fromthe pseudo-sheet structure 20, from being disturbed by the electricallyconductive linear bodies 22. Further, when the interval between adjacentelectrically conductive linear bodies 22 is within the above mentionedrange, the electrically conductive linear bodies are arranged in arelatively dense state. Therefore, improvements in the function of thesheet 10 can be achieved, such as, for example, maintaining theresistance of the pseudo-sheet structure low, allowing a uniformdistribution of temperature rise, and the like.

The interval L between adjacent electrically conductive linear bodies 22is obtained by observing the electrically conductive linear bodies 22 inthe pseudo-sheet structure 20 using a digital microscope, and bymeasuring the interval between two adjacent electrically conductivelinear bodies 22.

Note that, the interval L between two adjacent electrically conductivelinear bodies 22 refers to a length along the direction in which theelectrically conductive linear bodies 22 are arranged, and a lengthbetween the opposed portions of the two electrically conductive linearbodies 22 (see FIG. 2). In a case in which the electrically conductivelinear bodies 22 are arranged at irregular intervals, the interval L isthe mean value of the intervals between every two adjacent electricallyconductive linear bodies 22. It is preferable that the electricallyconductive linear bodies 22 are arranged at roughly regular intervals inthe pseudo-sheet structure 20, in terms of facilitating the control ofthe value of the interval L, and securing uniformity in functions suchas light transmittance and heat-generating performance.

The electrically conductive linear bodies 22 have a diameter D of from 5μm to 75 μm. The electrically conductive linear bodies 22 morepreferably have a diameter D of from 8 μm to 60 μm, and still morepreferably from 12 μm to 40 μm, in terms of preventing an increase inthe sheet resistance, and improving the heat-generating efficiency anddielectric breakdown properties of the sheet after being subjected tothree-dimensional molding.

When the diameter D of the electrically conductive linear bodies 22 isadjusted within the range of from 5 μm to 75 μm, in a case in which theelectrically conductive linear bodies 22 are linear bodies formed in awave pattern, as will be described later, the straightening of theelectrically conductive linear bodies 22, which occurs when the sheet 10is subjected to three-dimensional molding, is less likely to beinterfered with by an adjacent layer (such as the adhesive layer 32). Inparticular, when the diameter D of the electrically conductive linearbodies 22 is 12 μm or more, the sheet resistance of the pseudo-sheetstructure 20 is more easily reduced. In a case in which aheat-generating sheet for use in three-dimensional molding is used asthe sheet 10 to be coated on the surface of a molded article, and whenthe coated surface is touched by a hand, there is a tendency thatbulging of the resin protective layer 30 due to the underlyingelectrically conductive linear bodies 22 is more likely to be perceived.However, according to this heat-generating sheet for use inthree-dimensional molding, the bulging of the resin protective layer 30can be easily prevented.

The diameter D of the electrically conductive linear bodies 22 isobtained by: observing the electrically conductive linear bodies 22 inthe pseudo-sheet structure 20 using a digital microscope; measuring thediameter of the electrically conductive linear bodies 22 at randomlyselected 5 points; and calculating the mean value of the measureddiameters, to be taken as the diameter D.

The electrically conductive linear bodies 22 preferably have a volumeresistivity R of from 1.0×10⁻⁹ Ω·m to 1.0×10⁻³ Ω·m, and more preferablyfrom 1.0×10⁻⁸ Ω·m to 1.0×10⁻⁴ Ω·m. When the volume resistivity R of theelectrically conductive linear bodies 22 is within the above range, asurface resistance of the pseudo-sheet structure 20 is more easilyreduced.

The measurement of the volume resistivity R of the electricallyconductive linear bodies 22 is carried out as follows. First, thediameter D of the electrically conductive linear bodies 22 is obtainedaccording to the method describe above. Next, a silver paste is appliedon both ends of one of the electrically conductive linear bodies 22 andthe resistance at a portion corresponding to a length of 40 mm ismeasured, thereby obtaining a resistance value of the electricallyconductive linear body 22. Then, a cross-sectional area of theelectrically conductive linear body 22 is calculated, assuming that theelectrically conductive linear body 22 is in the form of a column havingthe diameter D. The thus calculated value of the cross-sectional area ismultiplied by the value of the above measured length, and the obtainedvalue is taken as the volume of the electrically conductive linear body22. The resistance value obtained above is divided by this value ofvolume, thereby calculating the volume resistivity R of the electricallyconductive linear body 22.

The electrically conductive linear bodies 22 are not particularlylimited as long as the electrically conductive linear bodies areelectrically conductive. Each of the electrically conductive linearbodies 22 may be, for example, a linear body including a metal wire, ora linear body including an electrically conductive thread. Theelectrically conductive linear body 22 may also be a linear bodyincluding a metal wire and an electrically conductive thread (such as alinear body obtained by twisting a metal wire and an electricallyconductive thread).

As will be described later, in a case in which the electricallyconductive linear bodies 22 are formed in a wave pattern, and theelectrically conductive linear bodies 22 are straightened and extendedfollowing the extension of the sheet 10 when the sheet 10 is extended bybeing subjected to three-dimensional molding, a strong adhesion betweenthe electrically conductive linear bodies 22 and the adhesive layer 32interferes with the extension of the electrically conductive linearbodies 22.

When a linear body including a metal wire or a linear body including anelectrically conductive thread is used as the electrically conductivelinear bodies 22, at this time, the electrically conductive linearbodies 22 will be in a state moderately adhered to the adhesive layer32. Thus, even when the electrically conductive linear bodies 22 formedin a wave pattern are straightened and extended, following the extensionof the sheet 10 due to three-dimensional molding, it is possible tofacilitate the peeling of the electrically conductive linear bodies 22from the adhesive layer 32, thereby facilitating the extension of theelectrically conductive linear bodies 22.

Since a linear body including a metal wire and a linear body includingan electrically conductive thread both have a high thermal conductivityand a high electrical conductivity, the use thereof as the electricallyconductive linear bodies 22 facilitates an improvement in the lighttransmittance, while reducing the surface resistance, of thepseudo-sheet structure 20. Further, a rapid generation of heat is morelikely to be achieved. In addition, linear bodies having a smalldiameter are more easily obtained, as described above.

The linear body including a metal wire may be a linear body composed ofa single metal wire, or a linear body obtained by twisting a pluralityof metal wires.

Examples of the metal wire include: a wire containing a metal such ascopper, aluminum, tungsten, iron, molybdenum, nickel, titanium, silver,or gold; and a wire containing an alloy (for example, a steel such asstainless steel or carbon steel, brass, phosphor bronze,zirconium-copper alloy, beryllium copper, iron-nickel, nichrome,nickel-titanium, Kanthal, Hastelloy, or rhenium-tungsten) containing twoor more kinds of metals. Further, the metal wire may be a metal wireplated with tin, zinc, silver, nickel, chromium, a nickel-chromiumalloy, or a solder. Alternatively, the metal wire may be a metal wirewhose surface is coated with a carbon material or a polymer to bedescribed later.

The metal wire may be, for example, a metal wire coated with a carbonmaterial.

When the metal wire is coated with a carbon material, the adhesionbetween the metal wire and the adhesive layer 32 is reduced. Therefore,by using a linear body including a metal wire coated with a carbonmaterial as the electrically conductive linear bodies 22, it is possibleto facilitate the peeling of the electrically conductive linear bodies22 from the adhesive layer 32, thereby facilitating the extension of theelectrically conductive linear bodies 22, even in a case in which theelectrically conductive linear bodies 22 formed in a wave pattern arestraightened and extended following the extension of the sheet 10 due tothree-dimensional molding. Further, when the metal wire is coated with acarbon material, a corrosion of the metal can also be inhibited.

Examples of the carbon material for coating the metal wire include:amorphous carbons such as carbon blacks, activated carbons, hardcarbons, soft carbons, mesoporous carbons, and carbon fibers; graphites;fullerenes; graphenes; and carbon nanotubes.

On the other hand, the linear body including an electrically conductivethread may be a linear body composed of a single electrically conductivethread, or may be a linear body obtained by twisting a plurality ofelectrically conductive threads.

Examples of the electrically conductive thread include a threadcontaining an electrically conductive fiber (such as a metal fiber, acarbon fiber, or a fiber of an ion-conductive polymer); a thread on thesurface of which a metal (such as copper, silver, or nickel) is platedor vapor-deposited; and a thread impregnated with a metal oxide.

Particularly preferred examples of the linear body including anelectrically conductive thread include a linear body including a threadformed using a carbon nanotube (hereinafter, also referred to as “carbonnanotube linear body”).

The carbon nanotube linear body can be obtained, for example, by drawingcarbon nanotubes in the form of sheets, from the end portion of a carbonnanotube forest (which refers to a grown form of carbon nanotubesobtained by allowing a plurality of carbon nanotubes to grow on asubstrate in an orientation vertical to the substrate; sometimes alsoreferred to as “array”), and the thus drawn carbon nanotube sheets areformed into bundles, followed by twisting the bundles of the carbonnanotube sheets. In a case in which the bundles of the carbon nanotubesheets are not twisted in a twisting step, in the production method asdescribed above, a carbon nanotube linear body in the form of a ribbonis obtained. In a case in which the bundles are twisted, on the otherhand, a linear body in the form of a thread is obtained. The carbonnanotube linear body in the form of a ribbon does not have a structurein which carbon nanotubes are twisted. In addition to the abovedescribed method, a carbon nanotube linear body can also be obtained byspinning a thread from a dispersion liquid of carbon nanotube.Production of a carbon nanotube linear body by spinning can be carriedout, for example, by a method disclosed in US Patent publication No.2013/0251619 (JP-A No. 2011-253140). It is preferable to use a carbonnanotube linear body in the form of a thread, in terms of obtaininguniformity in the diameter of carbon nanotube linear bodies. In terms ofobtaining a carbon nanotube linear body having a high purity, it ispreferable to obtain a carbon nanotube linear body in the form of athread, by twisting the carbon nanotube sheets. The carbon nanotubelinear body may be a linear body obtained by weaving two or more carbonnanotube linear bodies.

The carbon nanotube linear body may also be a linear body including acarbon nanotube and a metal (hereinafter, also referred to as “compositelinear body”). The use of the composite linear body facilitates animprovement in the electric conductivity, while maintaining the abovementioned characteristics of the carbon nanotube linear body. In otherwords, the resistance of the pseudo-sheet structure 20 can be easilyreduced.

Examples of the composite linear body include: (1) a composite linearbody which is obtained by drawing carbon nanotubes in the form of sheetsfrom the end portion of a carbon nanotube forest, and then forming thethus drawn carbon nanotube sheets into bundles, followed by twisting thebundles of the carbon nanotube sheets, wherein, in the above mentionedprocess of obtaining a carbon nanotube linear body, a single metal or ametal alloy is supported on the surface of the forest, sheets orbundles, or of the twisted linear body, by vapor-deposition, ionplating, sputtering, wet plating or the like; (2) a composite linearbody obtained by twisting bundles of the carbon nanotube sheets, alongwith a linear body composed of a single metal or a linear body composedof a metal alloy, or a composite linear body; and (3) a composite linearbody obtained by weaving a linear body composed of a single metal or alinear body composed of a metal alloy, or a composite linear body, witha carbon nanotube linear body or a composite linear body. When twistingthe bundles of the carbon nanotube sheets for obtaining the compositelinear body described in (2), a metal may be supported on the carbonnanotube, in the same manner as the composite linear body described in(1). Further, the composite linear body described in (3) is a linearbody obtained by weaving two linear bodies. However, the compositelinear body may be one obtained by weaving three or more of carbonnanotube linear bodies, or linear bodies composed of a single metal orlinear bodies composed of a metal alloy or composite linear bodies, aslong as at least one of a linear body composed of a single metal or alinear body composed of a metal alloy, or a composite linear body isincluded.

Examples of the metal contained in the composite linear body includesingle metals such as gold, silver, copper, iron, aluminum, nickel,chromium, tin, and zinc; and alloys (such as a copper-nickel-phosphorusalloy, and a copper-iron-phosphorus-zinc alloy) containing at least oneof the single metals.

(Resin Protective Layer)

The resin protective layer 30 is a layer which constitutes the surfaceof the sheet 10 when the sheet 10 has been subjected tothree-dimensional molding to be coated on a molded article. In otherwords, the resin protective layer 30 is a layer for protecting thepseudo-sheet structure 20, and functional layers (such as a thermallyconductive layer, a coloring layer, and/or a decorative layer) providedbetween the resin protective layer 30 and the pseudo-sheet structure 20,and for increasing the strength of the surface, and maintaining thefunctions and the like, of the sheet 10.

The resin protective layer 30 preferably contains a thermoplastic resin,in terms of three-dimensional moldability.

Examples of the thermoplastic resin include known resins such aspolyolefin resins, polyester resins, polyacrylic resins, polystyreneresins, polyimide resins, polyimideamide resins, polyamide resins,polyurethane resins, polycarbonate resins, polyarylate resins, melamineresins, epoxy resins, urethane resins, silicone resins, and fluorineresins; and mixed resins containing two or more kinds of the abovementioned resins.

It is also preferable that the resin protective layer 30 contains athermosetting resin, in terms of surface protection.

Examples of the thermosetting resin include known compositions such asepoxy resin compositions, resin compositions curable by a urethanereaction, and resin compositions curable by a radical polymerizationreaction.

Examples of the epoxy resin composition include a combination of anepoxy resin such as a multifunctional type epoxy resin, a bisphenol Atype epoxy resin, a bisphenol F type epoxy resin, a biphenyl type epoxyresin, or a dicyclopentadiene type epoxy resin, with a curing agent suchas an amine compound or a phenolic curing agent.

Examples of the resin composition curable by a urethane reaction includea resin composition containing a (meth)acrylic polyol and apolyisocyanate compound.

Examples of the resin composition curable by a radical polymerizationreaction include a radical polymerizable resin composition such as a(meth)acryloyl group or an unsaturated polyester. Examples thereofinclude a (meth)acrylic resin containing a radical polymerizable groupin its side chain (such as a (meth)acrylic resin obtained by reacting apolymer of a vinyl monomer (such as hydroxy (meth)acrylate, or glycidyl(meth)acrylate) containing a reactive group, with a monomer (such as a(meth)acrylic acid, or an isocyanato group-containing (meth)acrylate)containing a group capable of reacting with the reactive group of thecopolymer, and containing a radical polymerizable group); an epoxyacrylate containing a (meth)acrylic group obtained by allowing a(meth)acrylic acid or the like to react with a terminal of an epoxyresin; and an unsaturated polyester obtained by condensation of acarboxylic acid (such as fumaric acid) containing an unsaturated groupwith a diol.

The resin protective layer 30 may contain a thermally conductiveinorganic filler. In a case in which the resin protective layer 30contains a thermally conductive inorganic filler, it is possible toeffectively prevent the occurrence of uneven temperature rise(unevenness in the distribution of temperature rise) at the surface ofthe sheet 10.

The thermally conductive inorganic filler is not particularly limited,as long as the inorganic filler has a thermal conductivity of 10 W/mK ormore. Examples thereof include metal particles, metal oxide particles,metal hydroxide particles, and metal nitride particles. Specificexamples of the thermally conductive inorganic filler include knowninorganic particles such as silver particles, copper particles, aluminumparticles, nickel particles, zinc oxide particles, aluminum oxideparticles, aluminum nitride particles, silicon oxide particles,magnesium oxide particles, aluminum nitride particles, titaniumparticles, boron nitride particles, silicon nitride particles, siliconcarbide particles, diamond particles, graphite particles, carbonnanotube particles, metal silicon particles, carbon fiber particles,fullerene particles and glass particles.

The thermally conductive inorganic filler may be used singly, or incombination of two or more kinds.

The resin protective layer 30 preferably has a content of the thermallyconductive inorganic filler of from 0% by mass to 90% by mass, morepreferably from 2% by mass to 70% by mass, and still more preferablyfrom 5% by mass to 50% by mass, with respect to the total amount of theresin protective layer.

The resin protective layer 30 may contain a colorant. In a case in whicha colorant is incorporated into the resin protective layer 30 so thatthe resin protective layer 30 serves as a coloring layer, the resultingsheet has an increased ability to conceal the electrically conductivelinear bodies 22.

The colorant is not particularly limited, and a known colorant such asan inorganic pigment, an organic pigment, or a dye can be used,depending on the objective.

The resin protective layer 30 may contain other additives. Examples ofthe other additives include curing agents, anti-aging agents,photostabilizers, flame retardants, electrically conductive agents,antistatic agents, and plasticizers.

The surface of the resin protective layer 30 on the side of thepseudo-sheet structure 20 may be provided with an image(s) (such as adrawing, a letter, a pattern, and/or a design) formed with an imageforming material (such as an ink or a toner). The image can be formed bya known printing method such as gravure printing, offset printing,screen printing, ink-jet printing, or heat transfer printing. In thiscase, the resin protective layer 30 serves both as a decorative layer,and as a layer having a function to protect the decoration provided bythe image. Further, in this case, the sheet 10 can be used as a sheetfor use in three-dimensional decoration.

The resin protective layer 30 preferably has a thickness of, forexample, from 8 μm to 2,500 μm, more preferably from 10 μm to 2,300 μm,and still more preferably from 15 μm to 2,000 μm, in terms ofthree-dimensional moldability, and securing the protective function ofthe resin protective layer 30.

(Adhesive Layer)

The adhesive layer 32 is a layer containing an adhesive. When the sheet10 has a configuration in which the adhesive layer 32 is interposedbetween the resin protective layer 30 and the pseudo-sheet structure 20,with the adhesive layer 32 being in contact with the pseudo-sheetstructure 20, the adhesive layer 32 allows the sheet 10 to be easilycoated on the surface of a molded article. Specifically, in the sheet10, the adhesive layer 32 exposed from the pseudo-sheet structure 20(namely, from between the plurality of the electrically conductivelinear bodies 22 included therein) facilitates the adhesion between thesheet 10 and the surface of the molded article, as described above.

The adhesive layer 32 may be curable. When the adhesive layer is cured,a hardness sufficient for protecting the pseudo-sheet structure 20 isimparted to the adhesive layer 32. Further, the adhesive layer 32 whichhas been cured has an improved impact resistance, as a result of whichthe deformation of the cured adhesive layer 32 due to impact can also bereduced.

The adhesive layer 32 is preferably curable by an energy ray such as UVlight, a visible energy ray, an infrared ray, or an electron beam, sinceit allows the adhesive layer 32 to be cured easily in a short period oftime. Note that the expression “curing by an energy ray” includes heatcuring carried out by heating using an energy ray.

Conditions for carrying out curing by an energy ray vary depending onthe energy ray to be used. However, in the case of carrying out curingout by UV light irradiation, for example, UV light is preferablyirradiated at a dose of from 10 mJ/cm² to 3,000 mJ/cm², and for a periodof time from 1 second to 180 seconds.

The adhesive to be used in the adhesive layer 32 may be, for example, aso-called heat seal type adhesive which exhibits adhesiveness whenheated, or an adhesive which exhibits tackiness when humidified.However, the adhesive layer 32 is preferably a pressure sensitiveadhesive layer formed from a pressure sensitive adhesive, in terms ofease of use. The pressure sensitive adhesive to be used in the pressuresensitive adhesive layer is not particularly limited. Examples of thepressure sensitive adhesive include acrylic pressure sensitiveadhesives, urethane pressure sensitive adhesives, rubber pressuresensitive adhesives, polyester pressure sensitive adhesives, siliconepressure sensitive adhesives, and polyvinyl ether pressure sensitiveadhesives. Of these, the pressure sensitive adhesive is preferably atleast any one selected from the group consisting of acrylic pressuresensitive adhesives, urethane pressure sensitive adhesives, and rubberpressure sensitive adhesives. The pressure sensitive adhesive is morepreferably an acrylic pressure sensitive adhesive.

Examples of the acrylic pressure sensitive adhesive include: a polymercontaining a structural unit derived from an alkyl (meth)acrylatecontaining a straight chain alkyl group or a branched alkyl group(namely, a polymer obtained by at least polymerizing an alkyl(meth)acrylate); and an acrylic polymer containing a structural unitderived from a (meth)acrylate containing a ring structure (namely, apolymer obtained by at least polymerizing a (meth)acrylate containing aring structure). The “(meth)acrylate” is used herein as a term whichrefers to both “acrylate” and “methacrylate”, and the same applies forother terms similar thereto.

In a case in which the acrylic polymer is a copolymer, the form ofcopolymerization thereof is not particularly limited. The acryliccopolymer may be any of a block copolymer, a random copolymer, or agraft copolymer.

Among those mentioned above, the acrylic pressure sensitive adhesive ispreferably an acrylic copolymer containing: a structural unit (a1)derived from an alkyl (meth)acrylate (a1′) (hereinafter, also referredto as “monomer component (a1′)”) containing a chain alkyl group havingfrom 1 to 20 carbon atoms; and a structural unit (a2) derived from afunctional group-containing monomer (a2′) (hereinafter, also referred toas “monomer component (a2′)”).

Note, however, that the acrylic copolymer may further contain astructural unit (a3) derived from another monomer component (a3′) otherthan the monomer component (a1′) and the monomer component (a2′).

The number of carbon atoms in the chain alkyl group contained in themonomer component (a1′) is preferably from 1 to 12, more preferably from4 to 8, and still more preferably from 4 to 6, in terms of improving theadhesive property. Examples of the monomer component (a1′) includemethyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate,n-butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl(meth)acrylate, tridecyl (meth)acrylate, and stearyl (meth)acrylate.Among these monomer components (a1′), butyl (meth)acrylate and2-ethylhexyl (meth)acrylate are preferred, and butyl (meth)acrylate ismore preferred.

The content of the structural unit (a1) is preferably from 50% by massto 99.5% by mass, more preferably from 55% by mass to 99% by mass, stillmore preferably from 60% by mass to 97% by mass, and further still morepreferably from 65% by mass to 95% by mass, with respect to the totalamount (100% by mass) of the structural units in the acrylic copolymer.

Examples of the monomer component (a2′) include hydroxy group-containingmonomers, carboxy group-containing monomers, epoxy group-containingmonomers, amino group-containing monomers, cyano group-containingmonomers, keto group-containing monomers, and alkoxysilylgroup-containing monomers. Among these monomer components (a2′), ahydroxy group-containing monomer and a carboxy group-containing monomerare preferred.

Examples of the hydroxy group-containing monomer include 2-hydroxyethyl(meth)acrylate, 2-hydroxypropyl (meth)acrylate, 2-hydroxybutyl(meth)acrylate, 3-hydroxybutyl (meth)acrylate, and 4-hydroxybutyl(meth)acrylate. Of these, 2-hydroxyethyl (meth)acrylate is preferred.

Examples of the carboxy group-containing monomer include (meth)acrylicacid, maleic acid, fumaric acid, and itaconic acid. Of these,(meth)acrylic acid is preferred.

Examples of the epoxy group-containing monomer include glycidyl(meth)acrylate.

Examples of the amino group-containing monomer include diaminoethyl(meth)acrylate.

Examples of the cyano group-containing monomer include acrylonitrile.

The content of the structural unit (a2) is preferably from 0.1% by massto 50% by mass, more preferably from 0.5% by mass to 40% by mass, stillmore preferably from 1.0% by mass to 30% by mass, and further still morepreferably from 1.5% by mass to 20% by mass, with respect to the totalamount (100% by mass) of the structural units in the acrylic copolymer.

Examples of the monomer component (a3′) include: (meth)acrylatescontaining a ring structure such as cyclohexyl (meth)acrylate, benzyl(meth)acrylate, isobornyl (meth)acrylate, dicyclopentanyl(meth)acrylate, dicyclopentenyl (meth)acrylate, dicyclopentenyloxyethyl(meth)acrylate, imide (meth)acrylate, and acryloylmorpholine; vinylacetates; and styrenes.

The content of the structural unit (a3) is preferably from 0% by mass to40% by mass, more preferably from 0% by mass to 30% by mass, still morepreferably from 0% by mass to 25% by mass, and further still morepreferably from 0% by mass to 20% by mass, with respect to the totalamount (100% a by mass) of the structural units in the acryliccopolymer.

The monomer component (a1′) may be used singly, or in combination of twoor more kinds thereof; the monomer component (a2′) may be used singly,or in combination of two or more kinds thereof; and the monomercomponent (a3′) may be used singly, or in combination of two or morekinds thereof.

The acrylic copolymer may be crosslinked by a crosslinking agent.Examples of the crosslinking agent include epoxy crosslinking agents,isocyanate crosslinking agents, aziridine crosslinking agents, and metalchelate crosslinking agents, which are well known. In the case ofcrosslinking the acrylic copolymer, a functional group derived from themonomer component (a2′) can be used as a crosslinking site for reactionwith the crosslinking agent.

The pressure sensitive adhesive layer may contain an energy ray curablecomponent, in addition to the pressure sensitive adhesive.

Examples of the energy ray curable component include, in a case in whichthe energy ray is UV light, compounds containing two or more UV lightpolymerizable functional groups within one molecule, such as:trimethylolpropane tri(meth)acrylate, ethoxylated isocyanuric acidtri(meth)acrylate, ditrimethylolpropane tetra(meth)acrylate,tetramethylolmethane tetra(meth)acrylate, pentaerythritoltri(meth)acrylate, dipentaerythritol monohydroxypenta(meth)acrylate,dipentaerythritol hexa(meth)acrylate, caprolactone modifieddipentaerythritol hexa(meth)acrylate, 1,4-butylene glycoldi(meth)acrylate, 1,6-hexanediol di(meth)acrylate, dicyclopentadienedimethoxy di(meth)acrylate, polyethylene glycol di(meth)acrylate,oligoester (meth)acrylate, urethane (meth)acrylate oligomer, epoxymodified (meth)acrylate, and polyether (meth)acrylate.

The energy ray curable component may be used singly, or as a mixture oftwo or more kinds thereof.

In a case in which an acrylic pressure sensitive adhesive is used as thepressure sensitive adhesive, a compound containing a functional groupwhich reacts with a functional group derived from the monomer component(a2′) in the acrylic copolymer, and an energy ray polymerizablefunctional group, within one molecule, may be used as the energy raycurable component. Due to the reaction between the functional group inthis compound and the functional group derived from the monomercomponent (a2′) in the acrylic copolymer, side chains of the acryliccopolymer become polymerizable by the irradiation of an energy ray. In acase in which the pressure sensitive adhesive is one other than theacrylic pressure sensitive adhesive, a component having an energy raypolymerizable side chain may be used as a copolymer component other thanthe copolymer which serves as a pressure sensitive adhesive, as well.

In a case in which the pressure sensitive adhesive layer is energy raycurable, the pressure sensitive adhesive layer preferably contains aphotopolymerization initiator. Incorporation of a photopolymerizationinitiator serves to accelerate the rate at which the pressure sensitiveadhesive layer is cured by the irradiation of an energy ray. Examples ofthe photopolymerization initiator include benzophenone, acetophenone,benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropylether, benzoin isobutyl ether, benzoin benzoic acid, benzoin methylbenzoate, benzoin dimethyl ketal, 2,4-diethylthioxanthone,1-hydroxycyclohexyl phenyl ketone, benzyl diphenyl sulfide,tetramethylthiuram monosulfide, azobisisobutyronitrile, benzyl,dibenzyl, diacetyl, 2-chloroanthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2-benzothiazole-N,N-diethyldithiocarbamate, andoligo {2-hydroxy-2-methyl-1-[4-(1-propenyl)phenyl]propanone}.

The adhesive layer 32 may contain an inorganic filler. Incorporation ofan inorganic filler serves to further improve the hardness of the curedadhesive layer 32. The incorporation of an inorganic filler also servesto improve the thermal conductivity of the adhesive layer 32. Further,in a case in which an adherend includes glass as a main component, it ispossible to allow the sheet 10 to have a linear expansion coefficientclose to that of the adherend. This serves to improve a reliability ofan apparatus obtained by pasting the sheet 10 to the adherend, and bycuring the resultant, if necessary.

Examples of the inorganic filler include: powders of inorganic compoundssuch as silica, alumina, talc, calcium carbonate, titanium white, rediron oxide, silicon carbide, and boron nitride; beads obtained byspheroidizing the above described powders; single crystal fibers; andglass fibers. Of these, a silica filler and an alumina filler arepreferred as the inorganic filler. Further, the adhesive layer 32 maycontain, as the inorganic filler, a thermally conductive inorganicfiller which can be included in the resin protective layer 30. In thiscase, it is possible to obtain the same effect as in the case ofproviding an intermediate resin layer 36, as a thermally conductivelayer, which will be described later. The inorganic filler may be usedsingly, or in combination of two or more kinds thereof.

The inorganic filler is preferably surface modified by (subjected tocoupling with) a compound containing a curable functional group.

Examples of the curable functional group include hydroxyl group,carboxyl group, amino group, glycidyl group, epoxy group, ether group,ester group, and groups containing an ethylenically unsaturated bond.Examples of the compound containing a curable functional group includesilane coupling agents.

The inorganic filler is more preferably surface modified by a compoundcontaining an energy ray curable functional group, such as a groupcontaining an ethylenically unsaturated bond, because a fractureresistance of the cured adhesive layer 32 (the strength of the curedadhesive layer 32) can be easily maintained. Examples of the groupcontaining an ethylenically unsaturated bond include vinyl group, a(meth)acryloyl group, and maleimide group. Of these, a (meth)acryloylgroup is preferred, because of its high reactivity and generalversatility.

When the adhesive layer 32 contains an inorganic filler which is surfacemodified by the compound containing an energy ray curable functionalgroup, for example, the cured adhesive layer 32 will have a hightoughness, after subjecting the sheet 10 to three-dimensional molding tobe coated on the surface of a molded article.

In a case in which the adhesive layer 32 contains a surface-modifiedinorganic filler, the adhesive layer 32 preferably contains an energyray curable component, in addition to the inorganic filler.

The inorganic filler preferably has an average particle size of 1 μm orless, and more preferably 0.5 μm or less. When the inorganic filler hasan average particle size within the above range, the light transmittanceof the adhesive layer 32 is more easily improved. At the same time, ahaze of the sheet 10 (namely, of the adhesive layer 32) can be moreeasily reduced. The lower limit of the average particle size of theinorganic filler is not particularly limited, but is preferably 5 nm ormore.

The average particle size of the inorganic filler is obtained by:observing 20 particles of the inorganic filler by a digital microscope;measuring the maximum diameter and the minimum diameter of each particleof the inorganic filler and averaging the measured values to obtain thediameter of the particle; calculating the mean value of the diameters of20 particles, to be taken as the average particle size of the inorganicfiller.

The content of the inorganic filler is preferably from 0% by mass to 95%by mass, more preferably from 5% by mass to 90% by mass, still morepreferably from 10% by mass to 80% by mass, with respect to the totalamount of the adhesive layer 32.

The cured adhesive layer 32 preferably has a pencil hardness of HB ormore, more preferably F or more, and still more preferably H or more.When the cured adhesive layer has a pencil hardness within the aboverange, the function of the cured adhesive layer 32 to protect thepseudo-sheet structure 20 is further improved, thereby allowing for amore sufficient protection of the pseudo-sheet structure 20. The pencilhardness as used herein is a value measured in accordance with JISK5600-5-4.

The adhesive layer 32 may contain a colorant. Incorporation of acolorant allows for obtaining the same effect as in the case ofproviding the intermediate resin layer 36 as a coloring layer, whichwill be described later.

The adhesive layer 32 may contain other components. Examples of theother components include known additives such as organic solvents, flameretardants, tackifiers, UV absorbers, antioxidants, antiseptics,fungicides, plasticizers, antifoaming agents, and wettabilitycontrolling agents.

The adhesive layer 32 preferably has a thickness of from 3 μm to 150 μm,and more preferably from 5 μm to 100 μm, in terms of adhesion, forexample.

(Release Layer)

The release layer 34 has a function to protect the pseudo-sheetstructure 20 and the adhesive layer 32 exposed from the pseudo-sheetstructure 20 (namely, from between the plurality of the electricallyconductive linear bodies 22 included therein), before subjecting thesheet 10 to three-dimensional molding. When the release layer 34 isprovided, it is possible to prevent a breakage of the pseudo-sheetstructure 20 due to handling, and a reduction in the adhesive strengthof the adhesive layer 32. The release layer 34 is peeled off from thesheet 10, when subjecting the sheet 10 to three-dimensional molding.

The release layer 34 is not particularly limited. The release layer 34preferably includes: a release substrate; and a release agent layerformed by coating a release agent on the release substrate, in terms ofease of handleability, for example. Further, the release layer 34 mayinclude the release agent layer on only one surface of the releasesubstrate, or on both surfaces of the release substrate.

Examples of the release substrate include a paper substrate, a laminatedpaper obtained by laminating a thermoplastic resin (such aspolyethylene) on a paper substrate, and a plastic film. Examples of thepaper substrate include a glassine paper, a coated paper, and acast-coated paper. Examples of the plastic film include films ofpolyesters such as polyethylene terephthalate, polybutyleneterephthalate, and polyethylene naphthalate; and films of polyolefinssuch as polypropylene, and polyethylene. Examples of the release agentinclude olefin resins, rubber elastomers (such as butadiene resins, andisoprene resins), long-chain alkyl resins, alkyd resins, fluororesins,and silicone resins.

The thickness of the release layer 34 is not particularly limited. Ingeneral, the release layer 34 preferably has a thickness of from 20 μmto 200 μm, and more preferably from 25 μm to 150 μm.

The thickness of the release agent layer in the release layer 34 is notparticularly limited. In a case in which the release agent layer isformed by coating a solution containing a release agent on a releasesubstrate, the release agent layer 34 preferably has a thickness of from0.01 μm to 2.0 μm, and more preferably from 0.03 μm to 1.0 μm.

In a case in which a plastic film is used as the release substrate, theplastic film preferably has a thickness of from 3 μm to 150 μm, and morepreferably from 5 μm to 100 nm.

(Properties and the Like of Sheet)

In the sheet 10 according to the present embodiment, the total thicknessof the surface layers of the pseudo-sheet structure 20 (layers providedat the side of the pseudo-sheet structure 20 at which the resinprotective layer 30 is provided.) is from 1.5 times to 80 times thediameter of the electrically conductive linear bodies 22. The totalthickness of the surface layers of the pseudo-sheet structure 20 is morepreferably from 3 times to 40 times, and still more preferably from 5times to 20 times the diameter of the electrically conductive linearbodies 22, in terms of preventing the bulging of the surface of thesheet 10, and improving the heat-generating efficiency after thethree-dimensional molding.

Here, the resin protective layer 30, and other layers (such as theadhesive layer 32, and another resin layer) provided between the resinprotective layer 30 and the pseudo-sheet structure 20, correspond to thesurface layers of the pseudo-sheet structure 20, whereas a layer (suchas the release layer) provided at the opposite side of the pseudo-sheetstructure 20 from the side at which the resin protective layer 30 isprovided, does not correspond to the surface layer.

In a case in which a part or the entirety of the pseudo-sheet structure20 (namely, the electrically conductive linear bodies 22 constitutingthe pseudo-sheet structure) is embedded in a layer(s) (such as theadhesive layer 32, in the present embodiment) adjacent to the side atwhich the resin protective layer is provided, the thickness of thesurface layers of the pseudo-sheet 20 refers to the thickness thereof inthe region where the pseudo-sheet structure 20 (namely, the electricallyconductive linear bodies 22) is not embedded. The same applies for thethickness of each of the layers constituting the surface layers of thepseudo-sheet 20.

In the sheet 10, the ratio of the thickness of the thickness of theresin protective layer 30 to the thickness of the adhesive layer 32(thickness of the resin protective layer 30/thickness of the adhesivelayer 32) is preferably from 1/1 to 100/1, and more preferably from 2/1to 50/1, and still more preferably from 3/1 to 20/1.

When the sheet 10 is subjected to three-dimensional molding to be coatedon a molded article, the electrically conductive linear bodies 22 can beembedded not only in the adhesive layer 32, but also in a layer(s) (suchas the resin protective layer 30) included in the surface layers otherthan the adhesive layer 32. Accordingly, although the total thickness ofthe surface layers is equal to or greater than 1.5 times the diameter ofthe electrically conductive linear bodies 22, in the present embodiment,increasing the thickness of the adhesive layer 32 is not a sole meansfor realizing such a ratio of the total thickness of the surface layersto the diameter of the electrically conductive linear bodies 22.Therefore, it is not necessary to increase the thickness of the adhesivelayer 32 considering the case in which the electrically conductivelinear bodies 22 are embedded therein. In view of the durability of thesheet 10 after being subjected to three-dimensional molding, it ispreferable that the adhesive layer 32 is not excessively thick. Thus,the ratio of the thickness of the resin protective layer 30 to thethickness of the adhesive layer 32 is preferably within the above range.

In a case in which each of the electrically conductive linear bodies 22in the sheet 10 is a linear body including a metal wire coated with acarbon material, the adhesive layer 32 preferably has a peel force of 12N/25 mm or more, the peel force being measured 30 minutes after affixingthe adhesive layer 32 to a stainless steel plate.

When the metal wire is coated with a carbon material, the adhesionbetween the metal wire and the adhesive layer 32 is reduced. Therefore,when linear bodies including a metal wire are delivered on the surfaceof the adhesive layer 32 to be fixed thereon, during the production ofthe sheet 10, the linear bodies including a metal wire are more easilypeeled off from the adhesive layer 32. Accordingly, it is preferable toadjust the peel force of the adhesive layer 32 to 12 N/25 mm or more,and to use the adhesive layer 32 having a high adhesion strength.

The peel force of the adhesive layer 32 in this case is more preferably13 N/25 mm or more. However, the upper limit of the peel force of theadhesive layer 32 is preferably 35N/25 mm or less.

In a case in which each of the electrically conductive linear bodies 22in the sheet 10 is a linear body including an electrically conductivethread, on the other hand, the adhesive layer 32 preferably has a peelforce of 11 N/25 mm or less, the peel force being measured 30 minutesafter affixing the adhesive layer 32 to a stainless steel plate.Accordingly, by adjusting the peel force of the adhesive layer 32 to 11N/25 mm or less and using the adhesive layer 32 having a low adhesionstrength, it is possible facilitate the peeling of the electricallyconductive linear bodies 22 from the adhesive layer 32, and tofacilitate the extension of the electrically conductive linear bodies22, even in a case in which the electrically conductive linear bodies 22formed in a wave pattern are straightened and extended following theextension of the sheet 10 due to three-dimensional molding.

The peel force of the adhesive layer 32 in this case is more preferably10 N/25 mm or less. However, the lower limit of the peel force of theadhesive layer 32 is preferably 2 N/25 mm or less.

The peel force of the adhesive layer 32 in each of the above describedcases is measured as follows.

Surface layers (width: 25 mm) including the adhesive layer 32 areprepared, and the surface layers are affixed on a surface of a stainlesssteel plate, with the adhesive layer 32 facing the stainless steelplate. In this state, a load is applied to the resultant. After a lapseof 30 minutes, the resultant is subjected to the 180° peeling testdefined in JIS-Z0237 (2000). Specifically, the surface layers are pulledin a direction of 180° at a velocity of 300 mm/min, using a tensiletester, and a force required to peel the surface layers from thestainless steel plate is measured as the peel force of the adhesivelayer 32 in each of the cases. The conditions for applying the load arealso in accordance with the above described JIS.

In the sheet 10 according to the present embodiment, the sheet (namely,the pseudo-sheet structure 20 included therein) preferably has a surfaceresistance (Ω/□=Ω/sq.) of 800Ω/□ or less, more preferably from 0.01Ω/□to 500Ω/□, and still more preferably from 0.05Ω/□ to 300Ω/□. In terms ofreducing a voltage to be applied, the sheet 10 having a low surfaceresistance is required. When the sheet has a surface resistance of800Ω/□ or less, a reduction in the voltage to be applied can be easilyachieved.

The surface resistance of the sheet is measured according to thefollowing method. First, a silver paste is applied on both ends of thepseudo-sheet structure 20 in order to improve electrical connectivity.Subsequently, the sheet 10 is pasted on a glass substrate on both endsof which a copper tape is pasted, such that the silver paste comes incontact with the copper tape. Then the resistance is measured using anelectrical tester, and the surface resistance of the sheet iscalculated.

(Production Method of Sheet)

The method of producing the sheet 10 according to the present embodimentis not particularly limited. The sheet 10 is produced, for example,through the following steps.

First, a composition for preparing the adhesive layer 32 is coated onthe resin protective layer 30 to form a coated film. Then the coatedfilm is dried to prepare the adhesive layer 32. Subsequently, theelectrically conductive linear bodies 22 are arranged and disposed on alaminated body composed of the resin protective layer 30 and theadhesive layer 32 (namely, on the adhesive layer 32 included in thelaminated body), thereby forming the pseudo-sheet structure 20. Forexample, the laminated body composed of the resin protective layer 30and the adhesive layer 32 is disposed on an outer peripheral surface ofa drum member, and in this state, the electrically conductive linearbody 22 is helically wound onto the surface of the adhesive layer 32while rotating the drum member. Thereafter, the helically woundelectrically conductive linear body 22 is cut along the axial directionof the drum member, in a bundle. In this manner, the pseudo-sheetstructure 20 is formed, and at the same time, disposed on the surface ofthe adhesive layer 32. The resulting laminated body composed of theresin protective layer 30, the adhesive layer 32, and the pseudo-sheetstructure 20 is then retrieved from the drum member. Subsequently, therelease layer 34 is pasted at the opposite side of the pseudo-sheetstructure from the side at which the adhesive layer 32 is provided, inthe thus retrieved laminated body. The release layer 34 may be pasted onthe surface of the pseudo-sheet structure in the laminated body, in astate in which the laminated body is disposed on the drum member.According to above described method, it becomes possible to easilyadjust the interval L between adjacent electrically conductive linearbodies 22 in the pseudo-sheet structure 20, for example, by allowing afeeder of the electrically conductive linear body 22 to move along thedirection parallel to the axis of the drum member, while rotating thedrum member.

Alternatively, the sheet 10 may be prepared as follows. First, theelectrically conductive linear bodies 22 are arranged on the outerperipheral surface of the drum member to form the pseudo-sheet structure20, without disposing the laminated body composed of the resinprotective layer 30 and the adhesive layer 32 on the drum member. Thenthe laminated body composed of the resin protective layer 30 and theadhesive layer 32 (namely, the adhesive layer 32 included in thelaminated body) is pasted on one surface of the resulting pseudo-sheetstructure 20, and the release layer 34 is pasted on the other surface ofthe pseudo-sheet structure 20, thereby obtaining the sheet 10.

(Others)

The sheet 10 according to the present embodiment is used, for example,provided with a power feeding portion (electrodes) for feedingelectricity to the pseudo-sheet structure 20, although not shown in thefigures. The power feeding portion, for example, is formed using ametallic material, and electrically connected to the end portion of thepseudo-sheet structure 20. The joining together of the power feedingportion and the pseudo-sheet structure 20 is performed such that powercan be fed to each of the electrically conductive linear bodies 22 inthe pseudo-sheet structure 20, by a known method such as one using asolder.

(Method of Using Heat-Generating Sheet 10 for Use in Three-DimensionalMolding)

The sheet 10 according to the present embodiment is used for coating thesurface of a molded article 50, which is used in housings for electricalappliances, interior parts for vehicles, interior materials for buildingmaterials, and the like, by utilizing a three-dimensional molding methodsuch as TOM molding, film insert molding, or vacuum molding.

The molded article 50 includes, as a surface heat-generating body 511, acoating layer 541, which is formed by the sheet 10 from which therelease layer 34 has been peeled off (namely, by a laminated body of thepseudo-sheet structure 20, the adhesive layer 32, and the resinprotective layer 30). This molded article 50 can be used as a surfaceheat-generating article 521, which is used, for example, as aheat-generating article for melting ice and snow (such as lightingsection of traffic signal), or a heat-generating article for use in aheater (such as a heat-generating interior equipment for automobile)(see FIG. 7).

In other words, the sheet 10 according to the present embodiment allowsfor providing a surface heat-generating article which includes: asurface heat-generating body including: the pseudo-sheet structure 20including the electrically conductive linear bodies 22 each having adiameter of from 7 μm to 75 μm; and the resin protective layer 30provided at the side of one surface of the pseudo-sheet structure 20;wherein the thickness of the surface layers (the total thickness of thelayers provided at the side of the pseudo-sheet structure 20 at whichthe resin protective layer 30 is provided) is from 1.5 times to 80 timesthe diameter of the electrically conductive linear bodies 22.

Modified Examples

The sheet 10 and the surface heat-generating article 521 according tothe present embodiment are not limited to the above mentionedembodiments, and modifications and improvements can be made thereto. Themodified examples of the sheet 10 and the surface heat-generatingarticle 521 according to the present embodiment will now be described.In the description below, when the modified examples of the sheet 10 andthe surface heat-generating article 521 include the same members asthose described in the sheet 10 and the surface heat-generating article521 according to the present embodiment, the same symbols are given torefer to the members, and the description thereof will be omitted orsimplified.

First Modified Example

The sheet 10 according to the present embodiment is not limited to theabove described configuration, and may have another layer configuration.

For example, the sheet 10 may be a sheet 11, as shown in FIG. 3, whichhas a basic layer configuration shown in FIG. 2 and which also includesat least one of: 1) the resin layer 36 (hereinafter, also referred to as“intermediate resin layer 36”) provided between the resin protectivelayer 30 and the adhesive layer 32; 2) a resin layer 38 (hereinafter,also referred to as “lower resin layer 38”) provided at the oppositeside of the pseudo-sheet structure 20 from the side at which the resinprotective layer 30 is provided; or 3) a release layer 40 (hereinafter,also referred to as “upper release layer 40”) provided at the oppositeside of the resin protective layer 30 from the side at which thepseudo-sheet structure 20 is provided.

FIG. 3 shows the sheet 11 in which the intermediate resin layer 36, thelower resin layer 38, and upper release layer 40 are further provided tothe layer configuration of the sheet 10.

The intermediate resin layer 36 will now be described.

The intermediate resin layer 36 is a layer provided as a functionallayer, which serves, for example, as a thermally conductive layer, acoloring layer, a decorative layer, a primer layer, a layer forpreventing component migration, and/or the like. A plurality of layerseach having any of the functions described above may be provided as theintermediate resin layers 36. Alternatively, the intermediate resinlayer 36 may be a monolayer having a plurality of functions.

For example, in a case in which the intermediate resin layer 36 is athermally conductive layer, the intermediate resin layer 36 is composedof, for example, a layer containing a thermally conductive inorganicfiller and a thermoplastic resin. When the intermediate resin layer 36is a thermally conductive layer, the occurrence of uneven temperaturerise at the surface of the sheet 10 can be more effectively prevented.

Further, in a case in which the intermediate resin layer 36 is acoloring layer, the intermediate resin layer 36 is composed of, forexample, a layer containing a colorant and a thermoplastic resin. Whenthe intermediate resin layer 36 is a coloring layer, the resulting sheethas an increased ability to conceal the electrically conductive linearbodies 22. In this case, a layer having a light transmittance may beused as the resin protective layer 30.

Still further, in a case in which the intermediate resin layer is adecorative layer, the intermediate resin layer is composed of a resinlayer (such as a layer containing a thermoplastic resin) whose surfaceis provided with an image(s) (such as a drawing, a letter, a pattern,and/or a design) formed with an image forming material (such as an inkor a toner). The image can be formed by a known printing method such asgravure printing, offset printing, screen printing, ink-jet printing, orheat transfer printing. When the intermediate resin layer is adecorative layer, the sheet 11 can be used as a sheet for use inthree-dimensional decoration. In this case, a layer having a lighttransmittance is used as the resin protective layer 30.

The above described respective components included in the intermediateresin layer 36, and other components, may be the same as thoseexemplified for the resin protective layer 30.

The intermediate resin layer 36 preferably has a thickness of, forexample, from 5 to 1,300 μm, more preferably from 10 to 1,000 μm, andstill more preferably from 15 to 900 μm, in terms of three-dimensionalmoldability, and of securing the respective functions of the resinprotective layer 30.

Note, however, that a layer (coloring layer) containing a colorant isnot limited to the intermediate resin layer 36, and at least one layer,of layers provided at the side of the pseudo-sheet structure 20 at whichthe resin protective layer 30 is provided, can be used as the coloringlayer.

Further, the layer containing a thermally conductive inorganic filler(thermally conductive layer) is not limited to the intermediate resinlayer 36, and at least one layer, of the layers provided at the side ofthe pseudo-sheet structure 20 at which the resin protective layer 30 isprovided, can be used as the thermally conductive layer.

Still further, the decorative layer is not limited to the intermediateresin layer 36, and at least one layer, of the layers provided at theside of the pseudo-sheet structure 20 at which the resin protectivelayer 30 is provided, can be used as the decorative layer.

The lower resin layer 38 will now be described.

The lower resin layer 38 is a resin layer provided for heat welding thesheet 11 to the surface of a molded article, when the sheet 11 issubjected to three-dimensional molding to be coated on the surface ofthe molded article. In particular, the sheet 11 including the lowerresin layer 38 is suitable for use in a film insertion method, amongthree-dimensional molding methods.

For example, a layer including a thermoplastic resin is used as thelower resin layer 38. The above described respective components includedin the intermediate resin layer 36, and other components, may be thesame as those exemplified for the resin protective layer 30. Inparticular, the lower resin layer 38 is preferably a layer composed of apolyolefin such as polypropylene, a layer composed of anacrylonitrile-butadiene-styrene copolymer, or the like, in terms ofimproving thermal adhesiveness to a molded article.

The lower resin layer 38 preferably has a thickness of, for example,from 5 to 1,300 μmin, more preferably from 10 to 1,000 μm, and stillmore preferably from 15 to 900 μm, in terms of improving the thermaladhesiveness to a molded article.

The upper release layer 40 will now be described.

The upper release layer 40 has a function to protect the resinprotective layer 30 before and during the three-dimensional molding. Theupper release layer 40 is peeled off from the sheet 11 after thethree-dimensional molding. In particular, the sheet 11 including theupper release layer 40 is suitable for use in a film insertion method,among three-dimensional molding methods. The upper release layer 40 maybe peeled off from the sheet 11 before the three-dimensional molding, ifnecessary.

The upper release layer 40 is not particularly limited, as long as thelayer has a resistance to heat during the three-dimensional molding. Theupper release layer 40 may have, for example, the same configuration asthe release layer 34. In particular, the upper release layer 40 ispreferably a layer composed of a heat resistant resin film, or the like,in terms of securing the function to protect the resin protective layer30, and the resistance to heat during the three-dimensional molding.

In addition to the above, the sheet 10 according to the presentembodiment may include, for example, another adhesive layer which isdisposed at the opposite side of the pseudo-sheet structure 20 from theside at which the adhesive layer 32 is provided. The sheet 10 mayfurther include another release layer which is disposed at the oppositeside of the other adhesive layer from the side at which the pseudo-sheetstructure 20 is provided.

Second Modified Example

The sheet 10 according to the present embodiment may be, for example, asheet 12, as shown in FIG. 4, in which the electrically conductivelinear bodies 22 in the pseudo-sheet structure 20 are curved or bentperiodically or randomly. Specifically, the electrically conductivelinear bodies 22 may be formed in a wave pattern, such as a sine wave, arectangular wave, a chopping wave, a saw tooth wave, or the like. Inother words, the pseudo-sheet structure 20 may have, for example, astructure in which a plurality of the electrically conductive linearbodies 22 which are formed in a wave pattern and extendingunidirectionally are arranged at regular intervals in the directionperpendicular to the direction in which the electrically conductivelinear bodies 22 extend.

FIG. 4 shows the sheet 12 including the pseudo-sheet structure 20 inwhich a plurality of the electrically conductive linear bodies 22 whichare formed in a wave pattern and extending unidirectionally are arrangedat regular intervals in the direction perpendicular to the direction inwhich the electrically conductive linear bodies 22 extend.

By using linear bodies formed in a wave pattern as the electricallyconductive linear bodies 22, the electrically conductive linear bodies22 formed in a wave pattern can be straightened and extended easily, inthe direction in which the electrically conductive linear bodies 22extend, following the extension of the sheet 12, when the sheet 12 issubjected to three-dimensional molding to be coated on the surface of amolded article. Therefore, in the direction in which the electricallyconductive linear bodies 22 extend, the sheet 12 can be extended easilywithout being restricted by the electrically conductive linear bodies22.

At the same time, in the direction in which the electrically conductivelinear bodies 22 are arranged, the sheet 12 can be extended easilywithout being restricted by the electrically conductive linear bodies22, since the electrically conductive linear bodies 22 are not connectedwith each other.

In other words, the use of the linear bodies formed in a wave pattern asthe electrically conductive linear bodies 22 serves to prevent anextension failure of the sheet 12 or the breakage of the electricallyconductive linear bodies 22, when the sheet 12 is subjected tothree-dimensional molding to be coated on the surface of a moldedarticle.

Each of the electrically conductive linear bodies 22 formed in a wavepattern preferably has a wavelength λ (pitch of the wave pattern; seeFIG. 4) of from 0.3 mm to 100 mm, and more preferably from 0.5 mm to 80mm, in terms of preventing the extension failure of the sheet 12 or thebreakage of the electrically conductive linear bodies 22.

Likewise, in terms of preventing the extension failure of the sheet 12or the breakage of the electrically conductive linear bodies 22, each ofthe electrically conductive linear bodies 22 formed in a wave patternpreferably has an amplitude A (see FIG. 4) of from 0.3 mm to 200 mm, andmore preferably from 0.5 mm to 160 mm. The amplitude A refers to a total(peak to peak) amplitude.

Third Modified Example

The sheet 10 according to the present embodiment may be for example, asheet 13, as shown in FIG. 5 and FIG. 6. The sheet 13 includes thepseudo-sheet structure 20 in which electrically conductive linear bodieseach including: a first portion formed in a wave pattern having awavelength λ1 and an amplitude A1; and a second portion formed in a wavepattern having a wavelength λ2 and an amplitude A2, at least one ofwhich is different from the wavelength λ1 or the amplitude A1 of thefirst portion; are arranged.

In a case in which the three-dimensional molding causes a high degree ofextension of the sheet 10, the use of linear bodies formed in a wavepattern having a short wavelength or a large amplitude as theelectrically conductive linear bodies 22 allows for increasing thelength of the electrically conductive linear bodies 22 formed in a wavepattern when straightened, and allows the electrically conductive linearbodies 22 to easily follow the high degree of extension of the sheet 10.

However, in a case in which a molded article to be coated is athree-dimensional object having a complex shape, the degree of extensionvaries significantly depending on the region of the sheet 10, during thethree-dimensional molding of the sheet 10. As a result, the degree ofstraightening of the electrically conductive linear bodies 22 formed ina wave pattern also varies significantly depending on the region. Inother words, after the three-dimensional molding, some portions of theelectrically conductive linear bodies 22 are well straightened to bestraight or roughly straight, and some portions thereof are not wellstraightened and maintaining the wave pattern.

When the sheet 10 includes the pseudo-sheet structure 20 in which theelectrically conductive linear bodies 22 including portions thereofwhich are roughly straight and portions thereof which are notstraightened and maintaining the wave pattern, as described above, arearranged, the function of the sheet is decreased. For example, aconsumption of power may be increased due to increased resistance of thepseudo-sheet structure 20, resulting primarily from the presence of theportions of the electrically conductive linear bodies 22 which are notstraightened and maintaining the wave pattern. Alternatively, the amountof generated heat may be partially increased in the sheet, due to thepresence of a region in which an abundance ratio per unit area of theelectrically conductive linear bodies 22 is high.

Therefore, as the sheet 10, the sheet 13 is used in which each of theelectrically conductive linear bodies 22 is configured to include: thefirst portion formed in a wave pattern having the wavelength λ1 and theamplitude A1; and the second portion formed in a wave pattern having thewavelength λ2 and the amplitude A2, at least one of which is differentfrom the wavelength λ1 or the amplitude A1 of the first portion.

Specifically, the following configuration may be employed, depending onthe shape of a molded article to be coated by the three-dimensionalmolding. For example, the portion of each of the electrically conductivelinear bodies 22 present in a region of the sheet 13 with a high degreeof extension during the three-dimensional molding is configured as thefirst portion formed in a wave pattern having a short wavelength and/ora large amplitude. At the same time, the portion of each of theelectrically conductive linear bodies 22 present in a region of thesheet 13 with a low degree of extension during three-dimensional moldingis configured as the second portion formed in a wave pattern having along wavelength and/or a small amplitude.

In the case of using the electrically conductive linear bodies 22 eachincluding the first portion and the second portion, wherein the secondportion has a wavelength and an amplitude, at least one of which isdifferent from the wavelength or the amplitude of the first portion, asdescribed above, the degree of straightening of the linear bodies in therespective regions of the sheet will consequently be uniform. This isbecause, the first portion of each of the electrically conductive linearbodies 22 is straightened in a high degree in the region of the sheet 13with a high degree of extension, and the second portion of each of theelectrically conductive linear bodies 22 is straightened in a low degreein the region of the sheet 13 with a low degree of extension, during thethree-dimensional molding.

Accordingly, it is possible to prevent a decrease in the function of thesheet 13, such as an increased consumption of power due to increasedresistance of the pseudo-sheet structure 20, or a partial increase inthe amount of generated heat in the sheet due to the presence of aregion in which the abundance ratio per unit area of the electricallyconductive linear bodies 22 is high.

The sheet 13 of the third modified example will now be described infurther detail.

As shown in FIG. 5, each of the electrically conductive linear bodies 22in the sheet 13 includes a first portion 22A formed in a wave pattern, asecond portion 22B formed in a wave pattern, and a third portion 22Cformed in a wave pattern.

The first portion 22A has the wavelength λ1 and the amplitude A1.

The second portion 22B has the wavelength λ2 which is shorter than thewavelength X1, and the amplitude A2 which is the same as the amplitudeA1.

The third portion 22C has a wavelength λ3 which is the same as thewavelength λ1, and an amplitude A3 which is the same as the amplitude A1and amplitude A2.

In other words, the second portion 22B of each of the electricallyconductive linear bodies 22 has a longer length to be straightened ascompared to those of the first portion 22A and the third portion 22C, inthe direction in which the electrically conductive linear bodies 22extend.

The third portion 22C of each of the electrically conductive linearbodies 22, on the other hand, extends in the same degree as the firstportion 22A does, in the direction in which the electrically conductivelinear bodies 22 extend.

The region of the sheet 13 including the second portions 22B is definedas a region with a higher degree of extension as compared to the regionsof the sheet 13 including the first portions 22A and the third portions22C, respectively, during the three-dimensional molding.

When the sheet 13 including the pseudo-sheet structure 20 in which theelectrically conductive linear bodies 22 each including the abovedescribed first portion 22A to third portion 22C formed in a wavepattern are arranged, is subjected to three-dimensional molding to becoated on the surface of a molded article, the respective portions ofthe electrically conductive linear bodies 22 are straightened in varyingdegrees, depending on the degree of extension of the sheet 13. As aresult, it is possible to adjust every portion of the electricallyconductive linear bodies 22 to be in a roughly straight shape, after thethree-dimensional molding.

Accordingly, in the sheet 13 including the first portions 22A to thethird portions 22C formed in a wave pattern, a decrease in the functionof the sheet can be prevented.

In FIG. 5, a reference numeral 13A denotes the region of the sheet 13including the first portions 22A, a reference numeral 13B denotes theregion of the sheet 13 including the second portions 22B, and areference numeral 13C denotes the region of the sheet 13 including thethird portions 22C.

The electrically conductive linear bodies 22 in the sheet 13 are notlimited to the above described embodiment. For example, each of theelectrically conductive linear bodies 22 may have a first portion 22AA,a second portion 22BB, and a third portion 22CC, varying in amplitude,as shown in FIG. 6.

In this embodiment (see FIG. 6), the first portion 22AA has a wavelengthλ1 and an amplitude A2.

The second portion 22BB has a wavelength λ2 which is the same as thewavelength λ1, and an amplitude A2 which is smaller than the amplitudeA1.

The third portion 22CC has a wavelength λ3 which is the same as thewavelength λ1 and the wavelength λ2, and an amplitude A3 which is thesame as the amplitude A1.

In other words, the second portion 22BB of each of the electricallyconductive linear bodies 22 has a shorter length to be straightened ascompared to those of the first portion 22AA and the third portion 22CC,in the direction in which the electrically conductive linear bodies 22extend.

The third portion 22CC of each of the electrically conductive linearbodies 22, on the other hand, extends in the same degree as the firstportion 22AA does, in the direction in which the electrically conductivelinear bodies 22 extend.

The region of the sheet 13 including the second portions 22BB is definedas a region with a lower degree of extension as compared to the regionsof the sheet 13 including the first portions 22AA and the third portions22CC, respectively, during the three-dimensional molding.

When the sheet 13 including the pseudo-sheet structure 20 in which theelectrically conductive linear bodies 22 each including the abovedescribed first portion 22AA to third portion 22CC formed in a wavepattern are arranged, is subjected to three-dimensional molding to becoated on the surface of a molded article, the respective portions ofthe electrically conductive linear bodies 22 are straightened in varyingdegrees, depending on the degree of extension of the sheet 13. As aresult, it is possible to adjust every portion of the electricallyconductive linear bodies 22 to be in a roughly straight shape, after thethree-dimensional molding.

Accordingly, also in the sheet 13 including the first portions 22AA tothe third portions 22CC formed in a wave pattern, a decrease in thefunction of the sheet can be prevented.

In FIG. 6, a reference numeral 13AA denotes the region of the sheet 13including the first portions 22AA, a reference numeral 13BB denotes theregion of the sheet 13 including the second portions 22BB, and areference numeral 13CC denotes the region of the sheet 13 including thethird portions 22CC.

Although not shown in the Figures, the electrically conductive linearbodies 22 in the sheet 13 may have a first portion, a second portion,and a third portion varying both in wavelength and amplitude.

The electrically conductive linear bodies 22 are not limited to theabove mentioned embodiments, as long as each of the linear bodies 22includes: the first portion formed in a wave pattern having thewavelength λ1 and the amplitude A1; and the second portion formed in awave pattern having the wavelength λ2 and the amplitude A2, at least oneof which is different from the wavelength λ1 or the amplitude A1 of thefirst portion.

The varying degrees of the wavelength and the amplitude in therespective portions of the electrically conductive linear bodies 22 areadjusted depending on the shape of a molded article. Further, each ofthe electrically conductive linear bodies may include a straightportion. The wavelength and the amplitude in the respective portions maybe varied stepwise, or gradually.

Fourth Modified Example

The heat-generating article 521 according to the present embodiment maybe, as shown in FIG. 8, a surface heat-generating article 522 includinga surface heat-generating body 512 composed of: a first coating layer531 formed of the heat-generating sheet 10 for use in three-dimensionalmolding from which the release layer 34 has been peeled off (namely, alaminated body of the pseudo-sheet structure 20, the adhesive layer 32,and the resin protective layer 30); and a second coating layer 532provided on the surface of the first coating layer 531 on the sidefurther from the molded article 50. In the surface heat-generatingarticle 522 of the fourth modified example, the thickness of the surfacelayers in the heat-generating sheet 10 for use in three-dimensionalmolding need not be equal to or greater than 1.5 times the diameter ofthe electrically conductive linear bodies. However, the sum of thethickness of the surface layers in the heat-generating sheet 10 for usein three-dimensional molding and the thickness of the coating layers(namely, the total thickness of the layers provided at the side of thepseudo-sheet structure 20 at which the resin protective layer 30 of thesheet 10 is provided, in a state in which the first coating layer andthe second coating layer are formed on the molded article), is from 1.5times to 80 times the diameter of the electrically conductive linearbodies.

The surface heat-generating article 522 of the fourth modified examplecan be obtained, for example, by a method in which: the first coatinglayer 531 is formed on the molded article 50, by three-dimensionalmolding of the heat-generating sheet 10 for use in three-dimensionalmolding; and then the second coating layer 532 is further formed on thefirst coating layer 531, by three-dimensional molding of a sheet as amaterial for the second coating layer 532, thereby providing the surfaceheat-generating body 512 on the molded article 50.

The sheet as a material for the second coating layer 532 may be, forexample, a sheet in which the above described resin protective layer 30and the above described adhesive layer 32 are disposed one on another inlayers.

The first to fourth modified examples described above are merelyexamples, and the sheet 10 and the surface heat-generating article 521according to the present embodiment may have any of variousconfigurations, depending on the objective.

For example, although not shown in the figures, the sheet 10 accordingto the present embodiment may be a sheet in which a plurality of thepseudo-sheet structures 20 are arranged in the direction of the sheetsurface (direction along the sheet surface). The plurality of thepseudo-sheet structures may be arranged such that the directions inwhich the electrically conductive linear bodies 22 extend, of therespective pseudo-sheet structures, are parallel to each other, orperpendicular to each other.

EXAMPLES

The present disclosure will now be specifically described with referenceto Examples. Note, however, that the present disclosure is in no waylimited by each of these Examples.

Example 1

An adhesive sheet including: a polypropylene film, as a resin protectivelayer, having a thickness of 100 μm; and an acrylic pressure sensitiveadhesive layer, as an adhesive layer, provided on the polypropylene filmand having a thickness of 20 μm; was prepared. The peel force of theadhesive layer as measured according to the above described method was15 N/25 mm.

A carbon coated tungsten wire (diameter: 14 μm; product name: TGW-B;manufactured by TOKUSAI TungMoly Co., Ltd.) was prepared, to be used asan electrically conductive linear body.

Next, the above prepared adhesive sheet was wound about a drum memberwhose outer peripheral surface is made of rubber, such that the surfaceof the pressure sensitive adhesive layer faced radially outward and thatthe layer was not creased, and both end portions of the adhesive sheetin the circumferential direction were fixed with a double sided adhesivetape. The end of the wire wound about a bobbin was allowed to adhereonto the surface of the pressure sensitive adhesive layer of theadhesive sheet, at a location close to the end portion of the drummember. Then, the wire was wound onto the drum member while deliveringthe wire, and the drum member was allowed to move gradually in thedirection parallel to the axis of the drum, so that the wire ishelically wound about the drum member at regular intervals. In thismanner, a pseudo-sheet structure composed of wires, in which a pluralityof wires were arranged such that adjacent wires are regularly spacedapart from each other, was formed on the surface of the pressuresensitive adhesive layer of the adhesive sheet. When winding the wire,the drum member was allowed to vibrate as it moves along the drum axis,so that the wound wire was formed in a wave pattern. The wire was woundsuch that, in the resulting pseudo-sheet structure, the wires weredisposed regularly spaced apart from each other, at intervals of 1.7 mm.Each of the wires formed in a wave pattern had a wavelength λ (the pitchof the wave pattern) of 30 mm, and an amplitude A of 30 mm.

Next, on the surface of the pseudo-sheet structure formed on theadhesive sheet (namely, the surface at which the adhesive layer isexposed from between the wires), a release film (trade name: SP-381130(manufactured by Lintec Corporation)) as a release layer was pasted. Theadhesive sheet was then cut along with the pseudo-sheet structure andthe release layer in the direction parallel to the drum axis, to obtaina heat-generating sheet for use in three-dimensional molding.

Example 2

A heat-generating sheet for use in three-dimensional molding wasobtained in the same manner as in Example 1, except for using a carbonnanotube thread (diameter: 30 μm) obtained by drawing sheets from acarbon nanotube forest and then twisting the resulting sheets, insteadof the carbon coated tungsten wire, and for using an adhesive sheetincluding: a polypropylene film, as a resin protective layer, having athickness of 100 μm; and an acrylic pressure sensitive adhesive layer,as an adhesive layer, provided on the polypropylene film and having athickness of 20 μm (the peel force of the adhesive layer measured inaccordance with the above described method=10 N/25 mm); instead of theadhesive sheet used in Example 1.

Example 3

A heat-generating sheet for use in three-dimensional molding wasobtained in the same manner as in Example 1, except for using: apolypropylene film having a thickness of 800 μm; an adhesive layerhaving a thickness of 70 μm; and a copper wire (diameter: 70 μm, productname: Bare Copper Wire; manufactured by Arcor Electronics) instead ofthe carbon coated tungsten wire, and for adjusting the intervals betweenthe wires to 8 mm.

Example 4

A heat-generating sheet for use in three-dimensional molding wasobtained in the same manner as in Example 1, except for using: apolypropylene film having a thickness of 1,700 μm; an adhesive layerhaving a thickness of 20 μm; and a molybdenum wire (diameter: 25 μm;product name: TMG-BS; manufactured by TOKUSAI TungMoly Co., Ltd.,)instead of the carbon coated tungsten wire.

Example 5

A heat-generating sheet for use in three-dimensional molding wasobtained in the same manner as in Example 1, except for using apolypropylene film having a thickness of 15 μm, and an adhesive layerhaving a thickness of 10 μm.

Comparative Example 1

A heat-generating sheet for use in three-dimensional decoration wasobtained in the same manner as in Example 1, except for using apolypropylene film having a thickness of 8 μm, and an adhesive layerhaving a thickness of 10 μm.

Comparative Example 2

A heat-generating sheet for use in three-dimensional decoration wasobtained in the same manner as in Example 1, except for using: apolypropylene e film having a thickness of 2,500 μm; an adhesive layerhaving a thickness of 20 μm; and a tungsten wire having a diameter of 20μm (product name: TWG-B; manufactured by TOKUSAI TungMoly Co., Ltd.)

Comparative Example 3

A heat-generating sheet for use in three-dimensional molding wasobtained in the same manner as in Example 3, except for using apolypropylene film having a thickness of 15 μm, and an adhesive layerhaving a thickness of 40 μm.

The following evaluations were carried out, using the heat-generatingsheets for use in three-dimensional molding obtained in the respectiveExamples and Comparative Examples.

[Evaluation of Heat-Generating Efficiency (Measurement of Rate ofSurface Temperature Rise)]

A square sample having a size of 13 cm×13 cm was cut out from each ofthe heat-generating sheets for use in three-dimensional decorationprepared in Examples and Comparative Examples. The sample was fixed on asquare frame having a size of 10 cm×10 cm, and the resultant was heatedby a far infrared heater. After confirming that the center of the samplewas hanging down due to softening of the polypropylene film (resinprotective layer), a surface heat-generating body was formed on anadherend in the form of a hemisphere, using a vacuum forming technique.The adherend in the form of a hemisphere was made of polystyrene and hada diameter of 10 cm. A silver paste was applied on the end portions ofwires or carbon nanotube threads, which are exposed at both ends of thesurface heat-generating body without being coated by the adhesive layer.Then a copper tape having a width of 25 mm was pasted thereon so as toallow connection with the coated silver paste, thereby formingelectrodes. The resulting sample was left to stand in an environment of25° C. for 60 minutes, and then a voltage of 12 V was applied to thesurface heat-generating body, between both the electrodes, and thelength of time required until the temperature of the surface rose up to50° C. was measured.

[Evaluation of Bulging of Sheet Surface]

The surface of each of the samples which has been subjected to themeasurement of the rate of surface temperature rise was stroked by ahand. In a case in which irregularities were not perceived on the samplesurface, the sample was evaluated as being favorable. In a case in whichirregularities were perceived, on the other hand, the sample wasevaluated as being poor.

TABLE 1 Thickness Thickness of Resin of surface Evaluation Wireprotective Thickness layers of of heat- Evaluation Volume layer ofadhesive pseudo-sheet generating of bulging Diameter: Intervalresistivity (polypropylene layer structure: efficiency of sheet D (mm)(mm) Material (Ω · m) film) (μm) (μm) T (μm) T/D (sec) surface Example 114 1.7 Tungsten 1.0 × 10⁻⁷ 100 20 120 8.57 15 Favorable Example 2 30 1.7CNT 4.7 × 10⁻⁵ 100 20 120 4.00 25 Favorable Example 3 70 8 Copper 2.5 ×10⁻⁸ 800 70 870 12.43  15 Favorable Example 4 25 1.7 Molybdenum 6.6 ×10⁻⁸ 1700 20 1720 68.80  35 Favorable Example 5 14 1.7 Tungsten 1.0 ×10⁻⁷ 15 10 25 1.79 7 Favorable Comparative 14 1.7 Tungsten 1.0 × 10⁻⁷ 810 18 1.29 10 Poor Example 1 Comparative 20 1.7 Tungsten 1.0 × 10⁻⁷ 250020 2520 126.00  Not reached Favorable Example 2 to 50° C. Comparative 708 Copper 2.5 × 10⁻⁸ 15 40 55 0.79 7 Poor Example 3

It can be seen form the above results that each of the heat-generatingsheets for use in three-dimensional molding of the Examples of thepresent disclosure has a high rate of surface temperature rise and anexcellent heat-generating efficiency, and that the surface of each sheetafter being coated on the adherend is maintained smooth. This revealsthat the heat-generating sheets for use in three-dimensional molding ofthe Examples of the present disclosure have an excellent heat-generatingefficiency, and that the bulging of the sheet surface was prevented,even after the sheets have been subjected to three-dimensional molding.

The disclosure of Japanese Patent Application No. 2016-230551 isincorporated herein by reference in its entirety.

All publications, patent applications, and technical standards mentionedin this specification are herein incorporated by reference to the sameextent as if each individual publication, patent application, ortechnical standard was specifically and individually indicated to beincorporated by reference.

1. A heat-generating sheet for use in three-dimensional molding, theheat-generating sheet comprising: a pseudo-sheet structure in which aplurality of electrically conductive linear bodies extendingunidirectionally are arranged spaced apart from each other, and each ofthe electrically conductive linear bodies has a diameter of from 7 μm to75 μm; and a resin protective layer provided at a side of one surface ofthe pseudo-sheet structure; wherein a total thickness of layers providedat the side of the pseudo-sheet structure at which the resin protectivelayer is provided is from 1.5 times to 80 times the diameter of theelectrically conductive linear bodies.
 2. The heat-generating sheet foruse in three-dimensional molding according to claim 1, furthercomprising an adhesive layer provided between the pseudo-sheet structureand the resin protective layer.
 3. The heat-generating sheet for use inthree-dimensional molding according to claim 2, wherein a ratio of thethickness of the resin protective layer to the thickness of the adhesivelayer (thickness of the resin protective layer/thickness of the adhesivelayer) is from 1/1 to 100/1.
 4. The heat-generating sheet for use inthree-dimensional molding according to claim 1, wherein each of theelectrically conductive linear bodies is a linear body formed in a wavepattern.
 5. The heat-generating sheet for use in three-dimensionalmolding according to claim 1, wherein each of the electricallyconductive linear bodies is a linear body including a metal wire, or alinear body including an electrically conductive thread.
 6. Theheat-generating sheet for use in three-dimensional molding according toclaim 1, wherein each of the electrically conductive linear bodies is alinear body including a metal wire coated with a carbon material.
 7. Theheat-generating sheet for use in three-dimensional molding according toclaim 1, wherein the plurality of electrically conductive linear bodiesin the pseudo-sheet structure are arranged such that adjacentelectrically conductive linear bodies are regularly spaced apart fromeach other at intervals of from 0.3 mm to 12.0 mm.
 8. Theheat-generating sheet for use in three-dimensional molding according toclaim 1, wherein at least one layer, of the layers provided at the sideof the pseudo-sheet structure at which the resin protective layer isprovided, contains a colorant.
 9. The heat-generating sheet for use inthree-dimensional molding according to claim 1, wherein at least onelayer, of the layers provided at the side of the pseudo-sheet structureat which the resin protective layer is provided, contains a thermallyconductive inorganic filler.
 10. The heat-generating sheet for use inthree-dimensional molding according to claim 1, further comprising aresin layer provided at an opposite side of the pseudo-sheet structurefrom the side at which the resin protective layer is provided.
 11. Asurface heat-generating article, comprising, on a surface of a moldedarticle: a surface heat-generating body comprising: a pseudo-sheetstructure in which electrically conductive linear bodies are arrangedspaced apart from each other, and each of the electrically conductivelinear bodies has a diameter of from 7 μm to 75 μm; and a resinprotective layer provided at the side one surface of the pseudo-sheetstructure; wherein a total thickness of layers provided at the side thesurface of the pseudo-sheet structure at which the resin protectivelayer is provided is from 1.5 times to 80 times the diameter of theelectrically conductive linear bodies.
 12. The surface heat-generatingarticle according to claim 11, further comprising an adhesive layerprovided between the pseudo-sheet structure and the resin protectivelayer.
 13. The surface heat-generating article according to claim 12,wherein a ratio of the thickness of the resin protective layer to thethickness of the adhesive layer (thickness of the resin protectivelayer/thickness of the adhesive layer) is from 1/1 to 100/1.
 14. Thesurface heat-generating article according to claim 11, wherein each ofthe electrically conductive linear bodies is a linear body formed in awave pattern.
 15. The surface heat-generating article according to claim11, wherein each of the electrically conductive linear bodies is alinear body including a metal wire, or a linear body including anelectrically conductive thread.
 16. The surface heat-generating articleaccording to claim 11, wherein each of the electrically conductivelinear bodies is a linear body including a metal wire coated with acarbon material.
 17. The surface heat-generating article according toclaim 11, wherein the plurality of electrically conductive linear bodiesin the pseudo-sheet structure are arranged such that adjacentelectrically conductive linear bodies are regularly spaced apart fromeach other at intervals of from 0.3 mm to 12.0 mm.
 18. The surfaceheat-generating article according to claim 11, wherein at least onelayer, of the layers provided at the side of the pseudo-sheet structureat which the resin protective layer is provided, contains a colorant.